Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Intangible assets:
Goodwill	$ 1,047,497	$ 363,971
Accumulated amortization	(655,176)	(515,603)
Net intangible assets	$ 1,772,479	$ 839,433
Remaining Weighted Average Amortization Period in Years	19 years 2 months 12 days	21 years
Intangible liabilities:
Below market lease intangibles	$ 256,034	$ 229,495
Other lease intangibles	35,925	32,103
Accumulated amortization	(113,647)	(97,371)
Purchase option intangibles	3,568	13,549
Net intangible liabilities	$ 181,880	$ 177,776
Below market leases, remaining weighted average amortization period	14 years 2 months 12 days	14 years 1 month 6 days
Other lease intangibles, remaining weighted average amortization period	30 years 1 month 6 days	26 years 1 month 6 days
Finite-lived intangible liabilities, remaining weighted average amortization period	15 years 7 months 6 days	15 years 1 month 6 days
Intangibles
Net amortization expense	$ (142,700)	$ 74,600	$ 77,000
Estimated net amortization of the intangibles during 2016	98,700
Estimated net amortization of the intangibles during 2017	52,000
Estimated net amortization of the intangibles during 2018	42,900
Estimated net amortization of the intangibles during 2019	36,600
Estimated net amortization of the intangibles during 2020	33,900
Other intangibles
Intangible assets:
Other intangibles	$ 35,736	$ 36,030
Remaining Weighted Average Amortization Period in Years	8 years 7 months 6 days	7 years 10 months 24 days
Above market lease intangibles
Intangible assets:
Intangible assets	$ 155,161	$ 150,775
Remaining Weighted Average Amortization Period in Years	7 years	6 years 9 months 18 days
In-place and other lease intangibles
Intangible assets:
Intangible assets	$ 1,189,261	$ 804,260
Remaining Weighted Average Amortization Period in Years	20 years 10 months 24 days	24 years 6 months